1. Field of the Invention
The present invention relates to an image display apparatus such as a television telephone terminal capable of displaying an image received from another terminal.
2. Description of the Related Art
Conventional television telephone terminals include a type called a vertical body (e.g., see Japanese Patent Application Laid-Open No. 2000-333148), a type called a foldable body (e.g., see Japanese Patent Application Laid-Open No. 2001-165144 (corresponding to U.S. Pat. No. 6,708,046)), and a type in which a display unit is switchable between vertical and horizontal postures (e.g., see Japanese Patent Application Laid-Open No. 2003-134205). A recent sudden increase in use of television telephone terminals in which a television function and a telephone function are integrated has been accompanied by significant technical innovations in function, structure, and the like.
Conventional television telephone terminals will be described below with reference to FIGS. 14 and 15. FIG. 14 shows a television telephone terminal of a type generally called a vertical body. This television telephone terminal includes a display unit 1401 disposed in an upper part of the body, an operation unit 1402 disposed in a lower part of the body, and a slide switch 1403 for switching among three modes of the body, i.e., a power off mode, a television mode, and a telephone mode. In the case of selecting the power off mode, the slide switch 1403 is slid to an OFF position indicated by 1405 to switch to the power off mode. In the case of selecting the television mode, the slide switch 1403 is slid to a television position indicated by 1404 to switch to the television mode. In the case of selecting the telephone mode, the slide switch 1403 is slid to a telephone position indicated by 1406 to switch to the telephone mode.
On the other hand, another version of television telephone terminal which is shown in FIG. 15 is a type called a foldable body designed to improve portability. This television telephone terminal includes an input function side casing 1502 which is a fixed side casing, a plurality of input buttons 1504 for operations, and a display function side casing 1501 which is a movable side casing. The television telephone terminal further includes a hinge 1503 adapted to interconnect the input function side casing 1502 and the display function side casing 1501 to rotate relative to each other. An arrow 1505 indicates a direction in which the display function side casing 1501 is opened with respect to the input function side casing 1502. An arrow 1506 indicates a direction in which the display function side casing 1501 is folded with respect to the input function side casing 1502. To switch among three modes of the body, i.e., a power off mode, a television mode, and a telephone mode, dedicated push switches are provided. In the case of selecting the power off mode, a push switch 1508 is pushed to switch the body to the power off mode. In the case of selecting the television mode, a push switch 1509 is pushed to switch the body to the television mode. In the case of selecting the telephone mode, a push switch 1510 is pushed to switch the body to the telephone mode.
Common to the aforementioned television telephone terminals shown in FIGS. 14 and 15 is a configuration to set the main body to the power off mode, to the television mode, or to the telephone mode. Such setting is carried out by a user operating a dedicated input key or button to switch the modes. In such television telephone terminals, both keys are operable when the television mode is selected. Further, keys operable when the telephone mode is selected are arranged in the main body. For example, in FIG. 14, reference numerals 1407 and 1408 denote telephone directory menu switching keys for the telephone mode, and reference numerals 1410 and 1409 denote tuner frequency selection keys for the television mode. Referring to FIG. 15, reference numerals 1511 and 1512 denote telephone directory menu switching keys for the telephone mode, and reference numerals 1513 and 1514 denote tuner frequency selection keys for the television mode.
In the display unit 1401 of the conventional example of FIG. 14 and the display unit 1507 of the conventional example of FIG. 15, generally vertically long displaying is employed. In the telephone mode, an address book for making a call is displayed on the display unit 1401 or 1507, which is used for simultaneously displaying a number of telephone numbers so that a user can select one from a plurality of telephone numbers. In the television mode, a television receiving screen is displayed on the display unit 1401 or 1507. In the display unit 1401 or 1507, its aspect ratio is not changed irrespective of selection of the telephone mode or the television mode.
However, in the case of the aforementioned conventional television telephone terminals, generally, the vertically long display units are used as indicated by reference numeral 1401 of FIG. 14 and reference numeral 1507 of FIG. 15. Accordingly, when the television mode is selected, a vertically long image is obtained if television pictures are displayed while being matched with a display area of the display unit 1401 or 1507. However, most television pictures received in the television mode are horizontally long images. Therefore, displaying only vertically long images imposes a limitation on a range of receiving and viewing images, or the like, thus causing a lack of convenience for the user. Additionally, for example, the placement of the dedicated changeover switches on the main body to switch among a plurality of modes, i.e., the power off mode, the telephone mode, and the television mode, is a great obstacle to miniaturization and cost reduction of the main body.